ED is a common disease, mainly defined as that, the penis cannot erect, the penis cannot ejaculate, or both; according to statistics, the incidence of ED suffered by men over the age of 40 takes 1.9%, and the incidence of ED suffered by men over the age of 65 reaches 65%. There are approximately 125 million men suffering ED in different degrees in the world; and it estimates that 322 million men may suffer ED in 2025 (Moreland R B, et al, J Pharmacol Expther, 2001, 296 (2): 225-234). Thus, it has very important clinical values and social benefits for researching and developing new safe and effective drugs or new drug delivery systems to treat ED. And for this reason, some new drugs with novel structures and unique action mechanisms are promoted to the market or are being implemented with clinical researches and preclinical studies.
The Aildenafil citrate, of which the chemical name is 1-[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d] pyridine-5-group)-4-ethoxy-benzenesulfonyl]-cis-3,5-dimethylpiperazine citrate, the molecular formula is C23H32N6O4S.C6H8O7, the molecular weight is 680.73, and the chemical structure is:
is a new drug which is implemented with the clinical research and is effective for treating ED. The Chinese patent (of which the application number is 02100198.7) discloses the Aildenafil citrate and the preparation method thereof and the like, but does not relate to the Aildenafil citrate crystal form and the preparation method thereof.
During the process of researching and preparing the Aildenafil citrate, the invention finds that the Aildenafil citrate has multiple crystal forms; the crystal form O provided by the invention has high biological activity, high purity, good stability and excellent industrial production, is suitable for the technical process of the preparations, and is suitable for long-term storage.